All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=814800

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=e9ea0af3e9e6a6ec1db24c34c9117bda9ca59da380d6c21d382753f3ceb931f9


Bot(s) for this bug's original alert(s):

android-nexus5
android-nexus6
android-webview-nexus5X
android-webview-nexus6

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/169b7a00440000

 Issue 814798  has been merged into this issue.

 Issue 814799  has been merged into this issue.

📍 Pinpoint job started.
https://chromeperf.appspot.com/job/12f626df840000

📍 Pinpoint job started.
https://chromeperf.appspot.com/job/14cd5660440000

📍 Pinpoint job started.
https://chromeperf.appspot.com/job/12dd089f840000

📍 Couldn't reproduce a difference.
https://chromeperf.appspot.com/job/12dd089f840000

📍 Couldn't reproduce a difference.
https://chromeperf.appspot.com/job/12f626df840000

This is caused by temporary trace events added in issue 813824.

@simonhatch, interesting data point : it seems the dashboards run with tracing enabled but pinpoint doesn't? So if a regression is caused by adding fine grain trace events, pinpoint is unable to catch it?

The following revision refers to this bug:
  https://chromium.googlesource.com/v8/v8.git/+/3856d8d57d6f2798277182f20cd3a9810eae56ea

commit 3856d8d57d6f2798277182f20cd3a9810eae56ea
Author: Gabriel Charette <gab@chromium.org>
Date: Fri Feb 23 10:49:16 2018

Revert "[v8] Add finer grain trace events to EVACUATE_COPY step."

This reverts commit f64a87c45a3070088eaaba1162ffbabdadacb928.

Revert "[v8] Even finer grain trace events for EVACUATE_COPY step."

This reverts commit 2c1b6d383e5891aca3c2ddd451790fad0e286219.

Traces have been gathered by the bots. I'm still analyzing the results
but let's revert these for now to soothe the poor bots which are
running with v8.gc tracing enabled and regressing like crazy
because of this  crbug.com/814800 .

R=hpayer@chromium.org

Bug:  chromium:814800 , chromium:813824
Change-Id: If97c1ff5d14de18414c3b8d65ecb3aaf4f1bb32d
Reviewed-on: https://chromium-review.googlesource.com/934131
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Gabriel Charette <gab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51502}
[modify] https://crrev.com/3856d8d57d6f2798277182f20cd3a9810eae56ea/src/heap/mark-compact.cc

 Issue 814797  has been merged into this issue.

+dtu/mythria/ulan

re: #c10

AFAIK both Pinpoint and the waterfall both run with tracing enabled since metrics are actually computed from analyzing the resulting trace (tbmv2). If you click any of the values (far right group of boxes), Pinpoint gathers and surfaces all of the traces generated during a run and lists them in the UI.

In this case, it looks like the metric wasn't even generated though. I don't know much about this benchmark though or why the metric isn't being generated. Adding owners mythria/ulan for ideas on what happened.

Dave: Is there a bug open on surfacing better what happened during a run, I don't think it was obvious enough here that the run failed to produce values. Might be that the "No Differences" at the top is kinda throwing people off.

"No differences": Yes, it's tracked in https://github.com/catapult-project/catapult/issues/4231

📍 Couldn't reproduce a difference.
https://pinpoint-dot-chromeperf.appspot.com/job/14cd5660440000

📍 Couldn't reproduce a difference.
https://pinpoint-dot-chromeperf.appspot.com/job/169b7a00440000

 Issue 815082  has been merged into this issue.

 Issue 815080  has been merged into this issue.

 Issue 815081  has been merged into this issue.